Conventionally, nanowire electronic devices have been fabricated by growing the nanowires on the device substrates. However, the production costs of fabricating devices by this method are high and the scalability is low. Alternatively, nanowires may be separately fabricated by liquid phase synthesis, such as colloidal chemistry, or gas phase synthesis and subsequently deposited on the substrate. However, conventional nanowire prefabrication and deposition processes are costly and suffer from inferior quality.
Nanowires can be arranged in layers on surfaces in many ways for various purposes. For example the nanowires may be arranged to create transparent, conductive films. In one case, silver nanowires were arranged randomly and in parallel to the film surface forming a conductive layer at very low concentrations of nanowires (see Bergin et al., Nanoscale, 2012, 4, 1996-2004). Another purpose is producing nanostructured polymeric films has been to produce membranes, for example useful in different separation and purification steps (see European Published Application EP 2 436 722 A1). Here the nanoparticles are used as templates to create holes in the membrane and may be removed after crosslinking the membrane. There have also been attempts to align nanowires perpendicular to a supporting surface by controlling the rate of evaporation of the solvent (see Baker, Nano Lett., January 2010; 10(1): 195-201). However, this produced a fragile nanowire assembly. Furthermore, the drying method may be difficult to use on an industrial scale since the drying front (“coffee-ring effect”) will tend to transport material laterally, making a homogeneous monolayer difficult to attain.